Kristen Wiig has spent the years since the mega-success of “Bridesmaids” not exclusively churning out more blockbusters. Instead, she’s mostly been involved in smaller, challenging, even dramatic independent films. Her latest, after “Girl Most Likely,” “Hateship, Loveship” and “The Skeleton Twins,” is “Nasty Baby,” the latest from Chilean filmmaker Sebastian Silva, who previously did “Crystal Fairy” and “Magic Magic” — two films with another American star known for comedy, Michael Cera. In the film, Silva himself stars with Wiig as Freddy and Polly, two friends who, along with Freddy’s boyfriend (TV on the Radio’s Tunde Adebimpe), are trying to conceive a child together. It plays like a nice drama — until a bothersome neighbor (Reg E. Cathey), who’s till then skulked about the sidelines, forces the third act in a frightening and shocking direction.

How did you two meet?

Sebastian Silva: We met on OK Cupid. I saw her on a floater in a really beautiful pool. She was holding a drink, and I was like, “Who is she?” No, we were introduced by Alia Shawkat [who’s in the movie]. She knew I was looking for someone to play Polly and she just saw this connection.

You two have really lived-in chemistry in the movie. How long did it take for you two to click?

Kristen Wiig: It was pretty quick. We all sat around Sebastian’s kitchen table on day, and it was just easy the way conversation flowed.

Silva: And we just became more used to each other as we were shooting the film. It was 21 days. You spend so much time with people shooting movies; either you get closer or farther part. We just got closer. Every day we were more comfortable around each other and the friendship solidified.

That’s important for the way the scenes play out, which seem to be partly improvised, or at least loose. What was the script like?

Silva: There was a 20 page outline where every action is fleshed out and we knew exactly what needs to happen in every scenes. It was not one of those “mumblecore” movies, where it’s like, “OK, guys, action!” There were specific directions for each character in each scene. But no dialogue was written. We knew what information each of us had to convey in each scene, and we talked about how we were going to convey that.

Kristen, you have a long history of improv comedy. How was doing it for a naturalistic drama?

Wiig: I’d never improvised a dramatic scene, really, let alone a whole film. It really forces you to figure out who your character is and what they think about every possible thing. Everything you say has to come from that perspective. It’s very different from improvising comedy. With comedy you have to say in the realm of the scene and the character you’re playing, while looking for jokes.

There are jokes here, though.

Wiig: I wouldn’t say we were finding jokes. I’d say we were two people acting like they’re having fun and joking around together. When you’re with your friends, you have your own language and you make each other laugh. But you’re not necessarily trying to be funny. It’s just natural.

Silva: It’s normal, real fun. If a joke felt natural to the conversation, of course it’s welcome. But if not then it wasn’t. I would never give a direction like, “OK, everyone, let’s be fresh and funny.”

Wiig: You do say “Be fresh” a lot. [Laughs]

Silva. It’s true. [Laughs] No, I do not say that.

In terms of pitching this movie, both to people who would watch it and collaborators, it must be strange. It’s a drama about three friends making a baby, but then there’s this surprising dramatic incident that happens in the third act. How did you describe it?

Silva: I would just say it was a story about friends trying to make a family. They’re having tiny struggles. And in the meantime they’re getting into confrontations with an unwanted neighbor. And those two stories intertwine.

Wiig: People will either say, “Why is it different?” or “I love that it’s different.” It makes sense in the world of the movie. And it’s just such a different experience for the moviegoer, I think — to feel like you should hate someone you’ve liked for an hour and a half, then to see this horrible act but kind of understand it, then to not know what happens at the end. It’s a very refreshing way to tell a story on film.

Kristen, over the last few years you’ve done more small and challenging films than, say, blockbusters. Has that been a specific goal or just something that happened?

Wiig: It’s funny that people always think you make decisions that are really thought-out. [Laughs] I definitely did that with drama, though. I did want to do more dramatic roles. But ultimately you read and gravitate towards certain things and certain stories. And I love independent films. I love watching people make a movie happen, because it’s really hard to get money and to get people to sign and do it. Most of the scripts I’ve read that I’ve felt really connected to have been small films. There's something really great about people coming together to make these films. The spirit of independent films is really attractive.

Silva: And fresh.

Wiig: [Laughs]

SPOILER WARNING. Though the specifics of what happens in “Nasty Baby”’s final 15 minutes have been discussed in reviews and other interviews, we respect that people might want to go in semi-cold. At the same time we wanted to discuss the end with Silva and Wiig. Scroll down below for a discussion of these scenes if you’ve already seen the film or don’t mind being spoilered.

HERE BE SPOILERS.

The final scenes force everyone to go to dark places. Cathey’s character and Freddy wind up getting into a fight that ends with the former fatally stabbed and slowly bleeding to death. How was that shift for you two as actors, and as a filmmaker?

Wiig: The fact that we were in a little apartment with fake blood everywhere made it pretty easy to get into that hysterical state.

Silva: It was terrifying because I’ve never acted before. I was playing myself up until that moment where I had to reach a high-pitch emotional state. It felt natural to cry, to become hysterical and apologetic to the victim. The fact that Freddy was killing someone was torturous for him. It was a tragedy that he had to kill. He’s not a guy who’s killing for pleasure. In movies you see people killing each other while you eat popcorn. This is a murder that takes forever — a real-time killing that shows what a true murder would feel like.